How to Repair an Outboard Starter

by Will Charpentier

Starting motor troubles never seem to happen at a convenient time. After you check the battery and the ignition switch for loose wires and check to see the solenoid's getting "juice," you may even groan a little at the thought of repairing a starting motor. Troubles with an outboard's starting motor mean a mix of electrical and mechanical repair work. If you have a little experience with small electrical motors, a clean work space and a putty knife, you can disassemble your starter motor, replace the parts that need replacing and put it back together.

Wrap the jaws of a bench vise with a pair of old, thick towels. Remove the four bolts that hold the starter to the powerhead, using a small adjustable wrench. Place the starter in the bench vise with the pinion gear facing upward, the same direction in which the starter motor is installed on the powerhead. Pry the protective cap from the groove in the spacer with the back of the blade of a jackknife.

Push the spacer downward on the armature shaft until the snap-ring that acts as a retaining ring is exposed. Remove the retaining ring with a pair of snap-ring pliers. Pull the cup, spring and spacer from the armature shaft.

Unscrew the pinion gear and base by hand, and remove them from the armature shaft. Remove the screws that hold the mounting bracket to starter motor with a standard slotted screwdriver. Make a "matchmark" across the side of starter's two end caps, and the starter housing with a nail, to match the caps to the housing.

Remove the starter through-bolts and the end caps from the starter housing, then pull the armature assembly from the housing. The brush and terminal sets are mounted on the commutator cap of the starter. Take note of the correction orientation of each brush set and wire terminal before you remove them for cleaning or replacement. Replace any worn or unserviceable components.

Apply no more than a drop of SAE 10 motor oil on the armature shaft bearing surface and a light coating of machine oil to the threads of the armature shaft. Align the matchmarks on the drive cap and the starter housing, then insert the armature into the starter housing. Install the brush plate assembly on the commutator cap with the long lead in the slot. Place each brush spring into the bore in the brush plate and position each brush above its spring.

Position a brush holding tool over the brushes so as to hold them in the commutator cap. Align the match marks on the starter housing and the commutator cap and lower the armature, the drive cap and starter housing assembly onto the commutator cap. As the armature is seated, slowly withdraw the brush holding tool from between the cap and armature.

Apply a single drop of machine oil to each of the starter through-bolts before inserting them through the end cap. Tighten the through-bolts to 95 inch-pounds with a torque wrench. Seal the bolts with a liquid weatherstripping sealant.

Items you will need

Bench vise

Old towels

Small adjustable wrench

Jackknife

Snap-ring pliers

Standard slotted screwdriver

Nail

Replacement parts, as required

SAE 10 motor oil

Brush holding tool

Machine oil

Torque wrench

Liquid weatherstripping sealant

Putty knife

Tip

You can make a brush holding tool that will hold the brushes against the brush spring until the armature is installed. You can make a brush holding tool by cutting a slot hat's wide enough to slide around the bottom of the armature shaft, in the blade of a putty knife.

References

About the Author

Will Charpentier is a writer who specializes in boating and maritime subjects. A retired ship captain, Charpentier holds a doctorate in applied ocean science and engineering. He is also a certified marine technician and the author of a popular text on writing local history.